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Spodumene

Oxide Analysis Formula
Li2O 8.01% 1.00
Al2O3 27.41% 1.00
SiO2 64.59% 4.00
Oxide Weight 372.07
Formula Weight 372.07

Notes

The name is from the Greek spodos, meaning burnt to ash. Spodumene is a silicate mineral often referred to as lithium feldspar. Its mineral form is characterized by hard needle-like grains of brilliant white color. It is used in ceramics as a source of lithia.

Lithia is a very powerful flux, especially when used in conjunction with potash and soda feldspars. As one of only a few natural lithium source materials, spodumene is a valuable component in glass and ceramic/enamel glazes (Li2O reduces thermal expansion, melting temperature and viscosity of the glaze melt).

Spodumene is only slightly soluble (in contrast to lithium carbonate). Because spodumene is a natural combination of silica, alumina and lithia it melts better than a chemically equivalent mixture of lithium carbonate, kaolin and silica. Since almost all raw glazes contain kaolin and silica it is normally fairly easy to juggle recipe ingredients in a ceramic chemistry calculation program to introduce spodumene to replace lithium carbonate. Spodumene can also be substituted for part of the feldspar complement in a recipe without disturbing overall chemistry too much (other than substituting Li2O for KNaO).

Some types of spodumene do contribute to the formation of bubbles in the glaze slurry. You can wash spodumene before use to alleviate this issue (mix it well in plenty of hot water, allow to settle overnight, pour off the water the next day and dry it).

Spodumene is a little more readily fusible than petalite since it is higher in lithium.

Related Information

Sourcing Li2O from spodumene instead of lithium carbonate

Lithium carbonate is now incredibly expensive. The glaze on the left employs it. But I was able to source the Li2O from spodumene instead. Spodumene has a complex chemistry, but the oxides that it contains (other than Li2O) are those common to glazes anyway. Using my account at insight-live.com, I did the calculations and got a pretty good match in the formulas (lower section in the green boxes). Then I made 10 gram balls and did a melt flow test at 2200F (notice the long crystals in the pools of glass below the runways). And I glazed buff stoneware test (below the flow tests). Not surprisingly, this glaze is very runny. That's why the tiny yellow crystals grow during cooling, they produce the gold effect this recipe is known for. The spodumene version is very similar, perhaps better. Notice my calculated cost: $15.47/kg vs. $8.12/kg.

A problem with spodumene fluxed glazes: bubbles, surface dimples

This is a closeup of G3813B, a recipe with 11% spodumene. Although the glaze is very glossy, its surface is marred by tiny dimples, the remnant of broken and partially healed bubbles escapes. These bubbles were in the laydown and dried in place (the spodumene generates these in the slurry itself, making it frothy). This can be reduced by drop-and-hold firing techniques, but a better answer is to find a frit to source the Li2O.

Adding spodumene to this floating blue tones down the white patches

GA6-C (left) and GA6-E (right) at cone 6 oxidation. The E version adds 4% spodumene onto the 4% rutile in the C (the base is 80% Alberta Slip and 20% frit 3134). The spodumene eliminate the overly whitish areas that can appear. This glaze requires the "Slow Cool (Reactive Glazes)" firing schedule. It looks the best on dark bodies.

Spodumene glaze with natural iron stone concretion speckle

L3362A speckle test cone 10R (G2240 spodumene) using ground iron stone concretions (50% 70-100 mesh, 35% 50-70 mesh, 15% 40-50 mesh) at 0.5%, 0.3%, 0.1% (left to right).

Spodumene can bubble when mixed with water.

This is what happens when some spodumenes are mixed with water. They generate foam and bubbles. This is disruptive in glazes and can be alleviated by washing and drying the powder before use. Or calcining at 500-600F.

Spodumene ore

Spodumene ore: Typically refiners want 6% or more LiO2 content.

Links

Oxides Li2O - Lithium Oxide, Lithia
Glossary Pyroceramics
URLs http://www.talisonlithium.com/
Talison Lithium website
URLs http://www.cabot-corp.com/Search?Search=spodumene
Cabot Corp spodumene page
URLs http://en.wikipedia.org/wiki/Spodumene
Spodumene at Wikipedia
URLs http://www.minsocam.org/msa/Handbook/Spodumene.PDF
Technical and worldwide deposit info PDF
URLs http://www.minsocam.org/msa/Handbook/Spodumene.PDF
Technical and worldwide deposit info PDF
URLs http://www.geology.neab.net/minerals/spodumen.htm
Technical Information
Materials SC7.0 Spodumene
Materials Spodumene Concentrate
Materials Montebrasite Concentrate
Materials Triphylite
Materials Lepidolite
Materials Amblygonite
Materials Petalite
Materials Lithium Carbonate
Materials Foote Spodumene
Materials Australian Spodumene
Materials SC 1.1 Spodumene
Materials Feldspar
Materials FSC 2.1 Spodumene
Materials UGS Spodumene
Materials SC 1.2 Spodumene
Materials CGS 3.1 Spodumene
Suppliers Talison Lithium
Suppliers Cabot Corporation
Typecodes Feldspar
The most common source of fluxes for high and medium temperature glazes and bodies.
Typecodes Generic Material
Generic materials are those with no brand name. Normally they are theoretical, the chemistry portrays what a specimen would be if it had no contamination. Generic materials are helpful in educational situations where students need to study material theory (later they graduate to dealing with real world materials). They are also helpful where the chemistry of an actual material is not known. Often the accuracy of calculations is sufficient using generic materials.
Hazards Lithium Toxicology
Hazards Feldspar
Temperatures Spodumene melts (1418C-1428C)
Temperatures Spodumene converts to beta phase (1082C-)

Data

Frit Softening Point1421C M
Density (Specific Gravity)2.60

By Tony Hansen


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